Tuna: Yellowfin: Yellowfin Tuna Facts

Taxonomy

The Yellowfin tuna (Thunnus albacares) is a species of tuna belonging the the genus Thunnus and of the mackeral family Scombridae.

Species of Commercial Interest

Distribution

This species is found worldwide in tropical and subtropical seas, mostly ranging in the top 100 meters (330 ft) of the water column, although they are capable of diving to considerable depths. Tagging data show that trans-Atlantic migrations occur. In the eastern Pacific, this species ranges from southern California and the southwest and central eastern parts of the Gulf of California to Peru, including all of the oceanic islands. It may occur off Oregon and Washington during El Niño years.
For the sake of fisheries, Yellowfin has been divided into four stocks comprising the western and central Pacific (WCPO), eastern Pacific (EPO), Atlantic, and Indian Ocean (IO)stocks.

Biology

Yellowfin mature at an early age, have a moderate lifespan, are highly fecund, and are widely distributed, making them fairly resilient to fishing pressure. This is an open-water pelagic species that schools primarily by size, either in singular or multi-species groups. Larger fish frequently school with porpoises and are also associated with floating debris and other objects (FAD's). They subsist mainly on a diet of fishes, crustaceans and squids. Like all tunas, their body shape is evolved for speed, enabling them to pursue and capture fast-moving baitfish such as flying fish and mackerel.
The primary Atlantic spawning grounds are in the Gulf of Guinea, and to a lesser extent in the Gulf of Mexico. Spawning occurs throughout the year in the core areas of distribution at sea surface temperatures of 24°C or higher, but peaks are observed in the northern and southern summer months respectively. Spawning occurs almost entirely at night.

Sustainability

As one of the top three seafood items sold in the U.S., tuna is in high demand and many populations are declining. Yellowfin is caught in the Atlantic, Pacific, and Indian Oceans, and is mixed when is processed. Because of this, it becomes almost impossible to indentify a country of origin or the type of fishing gear used. Yellowfin is caught with troll, pole-and-line, longline and purse seine gear. There is little bycatch when yellowfin is caught with troll or pole-and-line gear. However, longlines result in large quantities of bycatch. Since there are no international laws to reduce bycatch, longlines are contributing heavily to the long-term decline of many species. The bycatch associated with purse seining for yellowfin can be quite high, especially when purse seines are set around natural floating objects (such as debris or FAD's).

Potential Health Concerns

Environmental Defense Fund has issued a consumption advisory for longline-caught Yellowfin tuna due to elevated levels of mercury. (No consumption advisories are listed for troll/pole-caught yellowfin as these methods catch younger tuna with lower mercury levels.)

References

Tuna: Yellowfin